For example, the Wonder Twins.
These two heroes have not gotten a break ever since their tenure among the Super Friends, alongside the likes of Invisible-Plane Wonder Woman, Giant-Seahorse-riding Aquaman, Black-Lightning-ripoff Black Vulcan, and those other three whose names unfortunately elude most mainstream superhero fans (Apache Chief, Samurai and Eldorado, for anybody besides me, who also cares). That said, these two, if taken into any serious capacity (and hopefully barring the further use of their ridiculous catchphrase 'Wonder Twin powers, activate!'), are not to be messed with.
A pair of fraternal twin siblings from the alien planet Exxor, Zan and Jayna possess the power to shapeshift any time they make physical contact. Zan could assume any form composed of any phase of water (whether solid, liquid or gas, and in any number of different shapes), while Jayna could assume the form of any animal (including extinct and alien creatures, as long as they weren't sentient--couldn't turn into another humanoid shape).
Okay, I understand that the use of powers and skills was often absurd on The Super Friends (see above examples with Wonder Woman and Aquaman) but that doesn't make the folks involved lame. It just means they were misused, to ridiculous and laughably absurd effect. Having said that, I think that a reboot is in order. I mean, they tried to make it work a couple of times by reinserting the Twins back into modern works, but it doesn't seem like any of it has stuck or will stick. Personally, I think it's time for a genuine change.
And the idea of a change isn't so much my concern about their looks (as they tried in Justice League Unlimited); personally, I think a modern version of their original appearances (like Superman got in the New 52 and Man of Steel) would do just fine. Rather, there should be a big change with their origins, and how their powers are portrayed. I mean, I know they weren't meant to be main characters, but personally, I don't see why they can't be. Batman, Superman, Wonder Woman, Green Lantern, Green Arrow, Hawkman, Booster Gold, Blue Beetle, even the much-maligned and underestimated Aquaman all have their own very popular and successful comic series.
Now, I know that, some years back, there was a rumor about a Wonder Twins movie coming out featuring Mila Kunis and Ashton Kutcher. The idea, based on your tastes, may be generally good, or generally bad (I, myself, would be just fine with it, but those two actors wouldn't be anywhere near my first choices). Still, whether it happens or not, I would like to see SOME reintroduction of the Wonder Twins back into the mainstream. And not as little goofy side-parts on freaking 'Teen Titans Go!'. And not as little background speaking roles on 'Justice League Unlimited'. And CERTAINLY not in any capacity like on The Super Friends. I want some actual respect paid to them, as befitting characters with such great conceptual potential.